Photophysics of ^tzAdenine and ^tzGuanine fluorescent nucleobases embedded into DNA and RNA

Autor(es)

Beal, Roiney ; Valverde, Danillo ; Goncalvez, Paulo F. B. ; Borin, Antonio Carlos

• Tipo de documento: Artigo Científico
• Fonte: Journal of Computational Chemistry; v. 44, n. 29, p. 10-pg., 2023-07-24.

Resumo

UV-VIS photoinduced events of (tz)A and (tz)G embedded into DNA and RNA are described by combining the Extended Multi-State Second-Order Perturbation Theory (XMS-CASPT2) and electrostatic embedding molecular mechanics methods (QM/MM). Our results point out that the S-1 (1)(pp* L-a) state is the bright state in both environments. After the photoexcitation to the S-1 (1)(pp* L-a) state, the electronic population evolves barrierless towards its minimum, from where the excess of energy can be dissipated by fluorescence. As the minimum energy crossing point structure between the ground and first bright states lies in a high-energy region, the direct internal conversion to the ground state is an unviable mechanism. Other spectroscopic properties (for instance, absorption and Stokes shifts) and comparisons with photochemical properties of canonical nucleobases are also provided. (AU)

• Processo FAPESP: 18/19454-5 - Estrutura e Fotofísica de Bases Nucleicas Fluorescentes e Pares de Bases Mediados por Metais de Transição
• Beneficiário: Antonio Carlos Borin
• Modalidade de apoio: Auxílio à Pesquisa - Regular